Solar panels in the motorhome

We have more and more devices that seem to be essential. We want to equip our motorhome or caravan in a fridge, coffee maker, computer, television and fashionable led lighting, which will illuminate every corner of the vehicle. But what about the power?

If we move often, normally a standard, on-board batteries should be sufficient. Worse, if we plan a longer stopover, away from sources of electrical energy. Preparing for such situations, we should think about installing solar panels on the roof.

What power in the motorhome?

In new camping cars and caravans, more and more often solar panels are installed on request, as an additional equipment. But the photovoltaic installation can be made at any time.

The most often installed sets of panels have the power of 100 to 200 W. Solar panels with less power can be taken into account if we want to supply a radio, small TV, laptop, LED lighting and other small devices. However, if we want to connect a large TV, a fridge and inverter, it’s better not to go below 100 W. However, in case of higher demand for electricity, for example if we have an electric boiler, we should install 200 W panels.

It is important, however, that the power of the solar system was adequate in relation to the capacity of the battery. If the battery capacity is 50 Ah, solar power should not exceed 50 W.

The weather is important

The panels effectiveness will depend on their type, the place of installation, but also on the weather. The power of panels is given with the solar power of 1000Wh/m2 taken under consideration, where sunbeams fall on a flat surface of the battery during one hour in the summer. Unfortunately, solar panels are able to convert only 15-20% of energy form the sunbeams. During cloudy weather or in winter, the result will be much worse and will amount only a few percent.

If there’s a possibility of changing the battery installation, it’s best to install it on the roof in the summer, and in the winter on the sides of the vehicle. It’s best if the sunbeams fall at the right angle. If we plan to install it permanently, the best place would be on the roof.

Changing the position of the panels is possible in the case of flexible structures – such batteries can be mounted also on uneven surfaces. The cheapest panels with the power of 60-70 W, transforming solar energy into the electricity of 12 V, will cost about 119 Euro. Better choose the models that have been designed as touristic, not stationary.

Installation isn’t hard

To install solar panels, you will need a mounting kit. An essential piece of equipment is the charge controller. It’s task will be to "ensure" that the battery is not overcharged. Most importantly, the controller converts the solar panels voltage into the battery voltage (12 V).

There are also controllers with a separate display that can be installed in the cab. This allows you to personally control charging of the batteries and operate the system.

After installing the panels, you will probably notice a gap between the roof and solar panels. It’s not a result of bad installation, but an intended procedure. The gap serves to cool the panels, what maintains its high efficiency. To avoid unpleasant whistles, you can install a special spoilers, adapted to the battery.

Battery installation is quiet simple. You just have to remember to firstly connect the battery to the voltage regulator, and only then connect the panels to the controller. The reverse sequence could damage the controller.